Mis-matched upper and lower

Ryan_

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Aug 5, 2010
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First ever post =]
I purchased a 1965 Sterncraft yesterday. Engine is 2.5, 4 cly, 120 hp, Pre Alpha outdrive. The guy I bought it from smoked the lower unit. He got his hands on an Alpha 1 lower unit, and mated the Pre Alpha upper with the Alpha 1 lower. He never got it back on the boat, just dumped the project for a REAL nice price.
When I put it in both gears, forward and back, it grabs and turns the prop as it should, but this is me turning it with my hand. It may not react the same way at 120 hp.
Can these 2 units be mated like this? If so, is there anything I should be careful of? If not, what exactly is the problem?
 

Ryan_

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Re: Mis-matched upper and lower

pics:

outdrive1.jpg

outdrive2.jpg

outdrive3.jpg
 

cr2k

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Re: Mis-matched upper and lower

Should not be a problem.
 

zbnutcase

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Re: Mis-matched upper and lower

Unless he can't fill the lower with oil if the upper doesn't have the oil passage, then it could be a problem!
 

Bt Doctur

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Aug 29, 2004
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Re: Mis-matched upper and lower

True, early units had no oil passage between them, might want to drop the lower and inspect the upper for the oil passage or upper and lower will not have oil.
 

Ryan_

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Re: Mis-matched upper and lower

True, early units had no oil passage between them, might want to drop the lower and inspect the upper for the oil passage or upper and lower will not have oil.

awesome, thanks guys.
I apologize, but I am very new to all this. I do not know what that passage looks like, or where it is located (I have not pulled these 2 pieces apart yet.)

If this is the case, would it be possible to fill them both individually, or would that be a bad idea?
 

Bt Doctur

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Re: Mis-matched upper and lower

you cant fill the bottom alone, there is no "vent" like the outboard lowers.
 

Ryan_

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Re: Mis-matched upper and lower

does anyone have a picture reference for this oil passage, before i take this thing apart? =]
 
Joined
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Re: Mis-matched upper and lower

That oil passage between both halves is on the starboard side and is sealed with the "quad-ring", looks like a flattened o-ring.
 

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Ryan_

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Re: Mis-matched upper and lower

well, checked out the old lower unit, it does indeed have a vent, so the upper unit most likely does not have the oil passage. Looks like it's time for a rebuild.
 

Fishermark

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Oct 19, 2003
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5,617
Re: Mis-matched upper and lower

I ask this mainly for my own edification - and who knows? It may even help the original poster! :D Doesn't the original lower unit have a pre-load pin that the newer lower units do not? Will this come into play with a mis-matched set like he has?
 

Ryan_

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Re: Mis-matched upper and lower

I ask this mainly for my own edification - and who knows? It may even help the original poster! :D Doesn't the original lower unit have a pre-load pin that the newer lower units do not? Will this come into play with a mis-matched set like he has?

yes, it would come into play. the guy that sold this to me removed that part from the original lower unit, and put it in the new one (and it works!). My only issue at this time is oil.
 

Bt Doctur

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Re: Mis-matched upper and lower

On the contrary, pin or no pin it dosent matter going into a upper. What is curious is the very early drives were 8 spline and the newer ones are 12 or 13 spline.Just how could you match the upper and lower units?
 

Ryan_

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Re: Mis-matched upper and lower

On the contrary, pin or no pin it dosent matter going into a upper. What is curious is the very early drives were 8 spline and the newer ones are 12 or 13 spline.Just how could you match the upper and lower units?

The previous owner put the 2 units together, so I am not sure what is going on inside of it. I'm taking them apart tomorrow, i'll post what I find.
 

Ryan_

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Re: Mis-matched upper and lower

well, I have the 2 units apart. The lower unit DOES have the oil passage on it, the older upper unit does not. It is indeed 8 spline, with a pin on top, which confirms my belief that the shaft was taken from the old lower unit (the upper unit is 8 spline as well, fits nicely). when i turn the shaft on the lower unit and switch gears, everything operates perfectly. The upper unit moves freely and smoothly as well. I think I may just get lucky here.

Here's what I think I'm going to do. I'll go out and buy a tap, and an appropriately sized hex head screw, and make a vent out of the oil passage in the lower unit. I will have to drop it off the upper every time I want to change the oil in it, but that's not really a big deal. What do you guys think?
 
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